1. Technical Field of the Invention
The present invention pertains in general to a method and apparatus for filtering data packets transmitted across a communication network and, more particularly, to a method and apparatus for filtering the transmission of data packets between a mobile station in a mobile radio network and an Internet Protocol (IP) type network.
2. Description of the Related Art
Packet data services are being introduced at an increasing rate into mobile radio networks. Packet data services provide an efficient connection between digital terminal equipment connected to mobile stations in a mobile radio network and remote hosts connected to the Internet. Using a packet data service, data is transmitted between the remote host and the digital terminal equipment as discrete data packets. The use of discrete data packets allows a mobile radio network operator to convey data from several mobile stations on a single channel and, further, to charge mobile station subscribers based on the quantity of data transmitted across the mobile radio network rather than on the duration of a connection between the mobile station and the remote host.
Using the packet data service, the mobile station subscriber connects digital terminal equipment, such as a personal computer, to the Internet or an Internet-like network such as an Intranet. This allows the mobile station subscriber to access remote hosts on the Internet and, in turn, allows remote hosts on the Internet to access the digital terminal equipment connected to the mobile station. For various reasons, mobile station subscribers and the mobile radio network operator may desire to control the flow of the IP traffic both to and from the mobile station. For example, since the mobile station subscriber is charged for data packets sent to the mobile station subscriber by a remote host, the mobile station subscriber may wish to filter IP traffic directed to the digital terminal equipment to certain authorized remote hosts.
In a similar fashion, the mobile radio network operator may wish to individually filter the ability of each mobile station to access remote hosts. For example, the mobile radio network operator may wish to create a virtual network, wherein a select group of mobile station subscribers and remote hosts have access to the virtual network. By establishing such virtual networks, the mobile radio network operator can charge different tariffs to each mobile station subscriber based on the subscriber's membership in one or more of the virtual networks.
Several techniques currently exist for controlling the transmission of data between computing devices over a network. These techniques apply both to hosts on the same network as well as to hosts located on different networks. For example, firewalls are commonly used as barriers between an internal network and external hosts to prevent the internal network from unauthorized access by the external hosts or others. The firewall also prevents the transmission of data from the external host to hosts on the internal network.
Other techniques for filtering traffic on a communication network involve filtering the communication of data to certain segments of a single or multiple communication networks. Such techniques are based on the address of the destination host and apply indiscriminately to all hosts. These filtering techniques are designed to increase the bandwidth of the communication network by filtering communication of the data to only those segments of the communication network necessary for the data to reach the destination host from the originating host.
It would be advantageous to devise a method and apparatus to individually filter IP traffic for each mobile station in a mobile radio network so as to filter communication between digital terminal equipment connected to a mobile station on a mobile radio network and remote hosts located on an Internet. It would also be advantageous if such a method and apparatus allowed both the mobile station subscriber and the mobile radio network operator to independently establish access privileges to and from the digital terminal equipment.